U.S. Pat. No. 245,786, issued Aug. 16, 1881 to L. A. Centlivre, entitled "Box Fastener", discloses an in-box latch having a compression spring that can be released by inserting a pencil or the equivalent through a hole in the front of the box. The box is proposed for shipping beer.
U.S. Pat. No. 742,563, issued Oct. 27, 1903 to C. W. Beehler, entitled "Box Fastener", discloses an in-box latch having a spring wire movable member and a semi-hook stationary sheet metal member coacting to retain the lid of a box closed until a pencil or the equivalent is passed through an adjacent hole in the box to push the movable member away from the sheet metal member.
This manual effort overcomes the retaining force of the spring wire member.